Frost Control of Strawberries Using Irrigation

Frost

• Frosty conditions manifest in the spring when ground temperatures drop below freezing. Generally, regions experience frosts on dry, cool nights. Strawberry plant tissues freeze when heat is lost during a frost. Damage occurs at the center of the plant. Gardeners may notice their frost-damaged strawberry plants have black centers, while foliage and berries remain uninjured. It takes a couple of hours or a few days for frost damage to become evident. A loss of 20 to 80 percent of the strawberry's yield may occur depending on the duration of the frost.

Irrigation

• Water releases heat as it freezes. When gardeners apply water during frosts, the warmth from the freezing water keeps the plant tissues from losing too much heat. Watering strawberry plants when temperatures dip below 21 degrees Fahrenheit will not prevent frost damage. In fact, strawberry plants become significantly injured when temperatures are around 26 degrees Fahrenheit. However, gardeners may not lose all of their strawberry plants even in a severe frost, because unopened buds are somewhat protected.

Using Irrigation During Frosts

• Turn the irrigation system on when ground temperatures hit 32 degrees Fahrenheit to prevent frost damage. The irrigation must be kept on until well after sunrise or after the ice melts off strawberry plants. Apply 1/10 to 1/8 inches of water each hour. Clouds may appear during a frost and temporarily raise temperatures. Refrain from turning off the irrigation, because temperatures may plummet after the cloud moves on. Temperatures must be warm enough to melt ice from plants before the irrigation can be turned off.

Other Factors

• It is important that the irrigation system evenly applies water to strawberry plants. Monitor your system before frost conditions occur. In addition, gardeners who do not have elaborate irrigation systems may use sprinklers to distribute water during frosts as long as the water evenly hits plants. Some gardeners spread a 3 to 4 inch layer of mulch around strawberry plants to help keep the soil warm and conserve water moisture. Straw mulch may be used to cover rows of strawberry plants during cold temperatures.